Resolution of a 2,6-methano-3-benzazocine-11-propanol analogue of buprenorphine showed that the biological activity resides in the levo antipode. An attempt to enhance agonist activity by preparation of N-methyl derivatives resulted in two compounds three and five times as potent as nalorphine as antagonists of phenazocine. These compounds are the most potent N-methyl narcotic antagonists reported to date.